Developmental disabilities represents an enormous problem for our society today costing the national economy billions of dollars per year. However, a large percent of individuals with developmental disabilities have unknown etiologies. Recent investigations of prenatal stress suggest that stressful life events during pregnancy have been associated with increased risk of childhood developmental problems such as speech and language problems, lowered IQ, and hyperactivity. However, because of the retrospective nature of these investigations, as well as other factors involved at the time of exposure to prenatal stress, it is difficult to accurately assess the role of prenatal stress in mediating these symptoms. The proposed research will use a nonhuman primate model to investigate the effects of the timing of prenatal stress on the developmental outcome of offspring. Behavioral and endocrine responses will be assessed in rhesus monkey infants from undisturbed, early-gestation stressed and mid-gestation stressed pregnancies. The primary measures will include: neonatal reflexes, neuromotor characteristics and capabilities; temperament; vagal tone; repeated observations of social-emotional behaviors; and behavioral and endocrine responses to challenge. Objectives include: (1) to characterize the development of prenatally stressed offspring in a longitudinal study; and (2) to evaluate the effect of timing of prenatal stress. The long term goal of this research will be on identifying the underlying mechanism of the prenatal stress effect, however, I believe that it is first necessary to discover at which time during pregnancy the negative effects from stress occur. Data representing social-interactional, behavioral, and psychobiological levels of analysis will be collected longitudinally from birth for each monkey infant. The research will be of considerable value for predicting the consequences of prenatal stress as well as detecting early predictors of such effects. This will provide important information for preventing and/or attenuating prenatal stress- related long-term developmental disorders in children.